TW202132373A - Method for forming a resist pattern and radiation-sensitive resin composition - Google Patents

Abstract

Provided are: a method for forming a resist pattern that, when a next-generation exposure technology is applied, demonstrates excellent performance such as sensitivity, resolution, etc. in the exposure step; and a radiation-sensitive resin composition. (C) The method for forming a resist pattern includes: a step (1) for forming a resist film in which the content of a radiation-sensitive acid-generating agent is 0.1 mass% or less; a step (2) for radiation exposure in which the resist film is irradiated with extreme ultra violet (EUV) or an electron beam (EB); and a step (3) for developing the resist film that has been subjected to radiation exposure in the step (2).

Description

Method for forming resist pattern, radiation-sensitive resin composition, method for processing substrate, and method for manufacturing metal film pattern

The present invention relates to a method for forming a resist pattern and a radiation-sensitive resin composition that can be used in the method for forming the resist pattern.

The photolithography technology using a resist composition is used in the formation of a fine circuit of a semiconductor element. As a representative procedure, for example, an acid is generated by exposing the film of the resist composition by interposing a mask pattern and irradiating with radiation, and reacting the acid as a catalyst between the exposed part and the unexposed part. There is a difference in the solubility of the resin with respect to the alkali-based or organic-based developer, thereby forming a resist pattern on the substrate.

In the photolithography technology, short-wavelength radiation such as ArF excimer lasers is used, or the radiation is combined with a liquid immersion exposure method (liquid immersion lithography) to advance pattern refinement. As the next generation technology, it is possible to realize the use of shorter wavelength radiation such as electron beam, X-ray and extreme ultraviolet (Extreme Ultraviolet, EUV). Research is also being carried out on resists containing styrene resins that improve the absorption efficiency of such radiation. Agent material (for example, Patent Document 1). [Prior Art Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2019-52294

[The problem to be solved by the invention] In the next-generation technology, the performance of resists equal to or higher than the previous ones are also required in terms of sensitivity or resolution. However, these characteristics cannot be obtained at a sufficient level by using the existing radiation-sensitive resin composition.

The object of the present invention is to provide a method for forming a radiation-sensitive resin composition and a resist pattern that can exhibit sensitivity or resolution at a sufficient level when the next-generation technology is applied.

[Means to solve the problem] The inventors of the present invention have repeatedly studied hard to solve this problem, and as a result, found that the above-mentioned object can be achieved by adopting the following structure, thereby completing the present invention.

That is, in one embodiment, the present invention relates to a method for forming a resist pattern, including: Step (1), forming (C) a resist film with a radiation-sensitive acid generator content of 0.1% by mass or less; Step (2), EUV or electron beam (EB) exposure is performed on the resist film; and In step (3), the resist film exposed in the step (2) is developed.

The method for forming a resist pattern of the present invention includes the step (1) of forming (C) a resist film in which the content of the radiation-sensitive acid generator is 0.1% by mass or less, so that the sensitivity in the exposure step can be exhibited at an excellent level Or resolution, etc. As the mechanism by which the effect is manifested, the scope of rights of the present invention is not necessarily limited by this estimation, but it is estimated that by setting the content of the (C) radiation-sensitive acid generator in the resist film to 0.1% by mass or less, The composition of the resist film is simplified to improve uniformity, or the adverse effects of the boundary surface of the exposed and unexposed areas caused by the acid generated during the exposure step are suppressed, and as a result, the performance of the resist is improved.

In addition, the method for forming a resist pattern of the present invention is preferably in one embodiment, In the step (1), the resist film is formed of (A) a radiation-sensitive resin composition containing (A1) in the absence of a radiation-sensitive acid generator Resin whose solubility changes by EUV or electron beam (EB) exposure. By having such a structure, even if it does not substantially contain the (C) radiation-sensitive acid generator as before, it can function as a resist film in the previous exposure step or the like. As a result, it can be more reliable Improve the performance of the resist.

In addition, the method for forming a resist pattern of the present invention is preferably set in one embodiment, In the step (1), the resist film is formed of (A) a radiation-sensitive resin composition, in the (A) radiation-sensitive resin composition, with respect to the total amount of components other than the solvent (B) , The (C) radiation-sensitive acid generator is 0.1% by mass or less. By having such a structure, it is possible to more simply form a resist film that does not substantially contain the (C) radiation-sensitive acid generator, and it is possible to more reliably improve the performance of the resist.

In addition, the method for forming a resist pattern of the present invention is preferably set in one embodiment, In the step (1), the resist film is formed of (A) a radiation-sensitive resin composition, and the (A) radiation-sensitive resin composition does not contain a radiation-sensitive acid generator. By having such a structure, it is possible to more simply form a resist film that does not substantially contain the (C) radiation-sensitive acid generator, and it is possible to more reliably improve the performance of the resist.

In addition, the method for forming a resist pattern of the present invention is preferably set in one embodiment, The resin whose solubility is changed (A1) is a resin whose solubility is changed to water-soluble or alkali-soluble. By having the structure, the properties of the resist can be improved more reliably.

On the other hand, the present invention, as another embodiment, relates to a radiation-sensitive resin composition, The radiation-sensitive resin composition contains (A2) a resin containing groups that are dissociated by EUV or electron beam (EB) exposure, (B) a solvent, and (C) a radiation-sensitive acid generator. In the radiation resin composition, the (C) radiation-sensitive acid generator is 0.1% by mass or less with respect to the total of the components other than the (B) solvent.

The radiation-sensitive resin composition of the present invention contains (A2) a resin containing a group that is dissociated by EUV or electron beam (EB) exposure, and in the radiation-sensitive resin composition, compared to (B) a solvent other than The total of the components of the (C) radiation-sensitive acid generator is 0.1% by mass or less, so the sensitivity or resolution in the exposure step can be exhibited at an excellent level. As the mechanism by which the effect is manifested, the scope of rights of the present invention is not necessarily limited by this estimation, but it is estimated that in the radiation-sensitive resin composition, with respect to the total of (B) components other than the solvent, (C) The content of the radiation-sensitive acid generator is set to 0.1% by mass or less, thereby simplifying the composition of the resist film, thereby improving uniformity, or the boundary surface of the exposed part and the unexposed part caused by the acid generated in the exposure step The adverse effects of the chromium are suppressed, and as a result, the performance of the resist is improved.

In addition, the radiation-sensitive resin composition of the present invention is preferably in one embodiment, It consists only of (A2) a resin containing groups dissociated by EUV or electron beam (EB) exposure, and (B) a solvent. By having such a structure, even if it does not substantially contain the (C) radiation-sensitive acid generator as before, it can function as a resist film in the previous exposure step or the like. As a result, it can be more reliable Improve the performance of the resist.

In addition, the radiation-sensitive resin composition of the present invention is preferably in one embodiment, The (A2) resin containing a dissociated group is a resin containing a group that dissociates to generate a carboxylic acid structure. By having such a structure, even if it does not substantially contain the (C) radiation-sensitive acid generator as before, it can function as a resist film in the previous exposure step or the like. As a result, it can be more reliable Improve the performance of the resist.

Hereinafter, embodiments of the present invention will be described in detail, but the present invention is not limited to these embodiments.

＜(A) Radiation-sensitive resin composition＞ The (A) radiation-sensitive resin composition of this embodiment (hereinafter, also simply referred to as "composition") contains predetermined resin (A0) and (B) solvent. The said composition may contain other arbitrary components as long as it does not impair the effect of this invention.

(Resin (A0)) The resin (A0) in the present invention is a resin: even if it does not substantially contain a radiation-sensitive acid generator, it can be exposed to exposure by changing the solubility to the developer by EUV or electron beam (EB) exposure, etc. Used as a resist film in a step or a development step. By using the resin (A0), it can be used as a resist film in the exposure step or the development step without substantially depending on the acid generated from the conventional exposure-sensitive radiation-sensitive acid generator by exposure. Furthermore, by simplifying the composition of the resist film, the uniformity is improved, or the adverse effects of the acid generated during the exposure step on the boundary surface of the exposed part and the unexposed part are suppressed. As a result, the performance of the resist can be improved. improve.

In the present invention, examples of the resin (A0) include (A1) resins whose solubility changes by EUV or electron beam (EB) exposure in the absence of a radiation-sensitive acid generator.

In the present invention, the so-called (A1) resin whose solubility is changed by EUV or electron beam (EB) exposure in the absence of a radiation-sensitive acid generator refers to a resin that does not substantially depend on the freeness by exposure In the case of conventional exposure-sensitive acid generated by a radioactive acid generator, it is a resin that changes its solubility in a developer by EUV or electron beam (EB) exposure. In addition, the "change in solubility" may include properties that increase or decrease the solubility to the developer.

In addition, as the resin whose solubility is changed in (A1), for example, a resin whose solubility is changed to water solubility or alkali solubility can be cited. Examples of resins that change into water-soluble or alkali-soluble resins include resins that regenerate or generate, for example, hydroxyl groups, carboxyl groups, amine groups, ionic groups, and sulfonic groups in the resin structure by exposure to light.

In addition, in the present invention, as the resin (A0), for example, (A2) a resin containing a group dissociated by EUV or electron beam (EB) exposure can be cited.

In the present invention, the so-called (A2) a resin containing a group dissociated by EUV or electron beam (EB) exposure means that it does not substantially depend on the exposure-sensing radiation generated by the radiation-sensitive acid generator as before. In the case of the acid, it is exposed to EUV or electron beam (EB) to form a resin that contains a group dissociated due to a detachment reaction or the like in the resin structure. In addition, the "dissociated group" includes, for example, a group capable of generating a hydroxyl group, a carboxyl group, an amino group, an ionic group, a sulfo group, etc. by dissociating the group by the exposure.

In addition, examples of (A2) resins containing groups dissociated by EUV or electron beam (EB) exposure include resins containing groups that dissociate to generate a carboxylic acid structure, and resins that contain groups that dissociate to generate a hydroxyl structure. Further, the so-called acid structural dissociation produced, for example, a carboxyl group (-COOH) or salt (carboxylic acid ester group, -COO ^-). The hydroxyl structure The term dissociation generated include alcoholic hydroxyl group or phenolic hydroxyl group (-OH) and a salt thereof (-O ^-) and the like.

In addition, the (A2) resin containing a dissociated group includes, for example, a structural unit having a group that dissociates to generate a carboxylic acid structure, and a structural unit that includes a group that dissociates to generate a hydroxyl structure. As a preferred example, a structural unit having a group that dissociates to generate a carboxylic acid structure, and at least one structural unit selected from a structural unit having a phenolic hydroxyl group and a structural unit having a polar group can be cited.

In addition, the structural unit having a polar group includes, for example, a structural unit selected from a structural unit having an alcoholic hydroxyl group, a structural unit having a lactone structure, a structural unit having a cyclic carbonate structure, and a structural unit having a sultone structure. At least one of them is a preferable example.

In addition, in the present invention, as the resin (A0), a structural unit (a1) containing a phenolic hydroxyl group and a resin containing a phenolic hydroxyl group-containing structural unit (a1) and containing it by EUV or electron beam (EB) exposure in the absence of a radiation-sensitive acid generator can be mentioned. A polymer assembly of the structural unit (a2) of the dissociated group (hereinafter, this resin is also referred to as "base resin").

The resin (A0) as the base resin may have other structural units other than the structural unit (a1) and the structural unit (a2). Hereinafter, each structural unit will be described.

[Structural unit (a1)] The structural unit (a1) is a structural unit containing a phenolic hydroxyl group. The resin (A0) has the structural unit (a1) and other structural units as necessary, so that the solubility to the developer can be adjusted more appropriately, and as a result, the sensitivity or resolution of the radiation-sensitive resin composition can be further improved The performance of resists such as high temperature and so on. In addition, in the case of using EUV, electron beam, etc. as the radiation irradiated in the exposure step of the resist pattern forming method, the resin (A0) has the structural unit (a1), and the structural unit (a1) contributes to the etching resistance The improvement of the properties and the improvement of the difference in the solubility of the developer between the exposed part and the unexposed part (dissolution contrast). In particular, it can be preferably applied to pattern formation by exposure using radiation with a wavelength of 50 nm or less, such as electron beam or EUV.

As said structural unit (a1), the structural unit etc. which are represented by following formula (af), for example are mentioned.

[化1]

In the formula (af), R ^AF1 is a hydrogen atom or a methyl group. L ^AF is a single bond, -COO-, -O- or -CONH-. R ^AF2 is a monovalent organic group having 1 to 20 carbons. n _f1 is an integer of 0-3. When n _f1 is 2 or 3, a plurality of R ^AF2 may be the same or different. n _f2 is an integer of 1-3. Here, n _f1 +n _f2 is 5 or less. n _af is an integer of 0-2.

As L ^AF , a single bond and -COO- are preferable.

From the viewpoint of providing the copolymerizability of the monomer of the structural unit (a1), when L ^AF is a single bond, the R ^{AF1 is} preferably a hydrogen atom. When L ^AF is -COO-, the R ^{AF1 is} preferably a methyl group.

Furthermore, the so-called organic group in the resin (A0) refers to a group containing at least one carbon atom.

Examples of the monovalent organic group having 1 to 20 carbons represented by R ^AF2 include, for example, a monovalent hydrocarbon group having 1 to 20 carbons, which contains a divalent hydrocarbon group at the end of the carbon-carbon or bonding bond side. A group of a heteroatom-containing group, a group obtained by substituting a part or all of the hydrogen atoms of the group and the hydrocarbon group with a monovalent heteroatom-containing group, and the like.

Examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms represented by R ^AF2 include alkyl groups such as methyl, ethyl, propyl, and butyl; alkenyl groups such as vinyl, propenyl, and butenyl; Chain hydrocarbon groups such as alkynyl groups such as ethynyl, propynyl and butynyl; cycloalkyl groups such as cyclopropyl, cyclopentyl, cyclohexyl, cyclooctyl, norbornyl, adamantyl, etc.; cyclopropenyl, ring Alicyclic hydrocarbon groups such as cycloalkenyl groups such as pentenyl, cyclohexenyl, norbornenyl; aryl groups such as phenyl, tolyl, xylyl, naphthyl, and anthryl groups; benzyl, phenethyl, naphthalene Aromatic hydrocarbon groups such as aralkyl groups such as methyl group and the like.

The R ^{AF2 is} preferably a chain hydrocarbon group, a cycloalkyl group, more preferably an alkyl group and a cycloalkyl group, and still more preferably a methyl group, an ethyl group, a propyl group, a cyclopentyl group, a cyclohexyl group, a cyclooctyl group, and Adamantyl.

Examples of the divalent heteroatom-containing group include: -O- _{, -CO-, -CO-O-, -S-, -CS-, -SO 2} -, -NR'-, these A combination of two or more of them. R'is a hydrogen atom or a monovalent hydrocarbon group.

Examples of the monovalent heteroatom-containing group include halogen atoms such as a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, a hydroxyl group, a carboxyl group, a cyano group, an amino group, and a mercapto group (-SH).

Among these, a monovalent chain hydrocarbon group is preferable, an alkyl group is more preferable, and a methyl group is still more preferable.

The n _{f1 is} preferably an integer of 0 to 2, more preferably 0 and 1, and still more preferably 0.

As said n _f2 , 1 and 2 are preferable, and 1 is more preferable.

As said n _af , 0 and 1 are preferable, and 0 is more preferable.

In the radiation-sensitive resin composition of the present invention, the structural unit (a1) may be a structural unit derived from hydroxystyrene.

As said structural unit (a1), the structural unit etc. which are represented by following formula (a1-1)-formula (a1-6) are preferable.

[化2]

In the formulas (a1-1) to (a1-6), R ^AF1 is the same as the formula (af).

Among these, structural unit (a1-1) and structural unit (a1-2) are preferable, and (a1-1) is more preferable.

Regarding the structural unit (a1) in the resin (A0), as the lower limit of the content ratio of the structural unit (a1), relative to all the structural units constituting the resin (A0), it is preferably 10 mol%, more preferably 15 mol% Ear%, more preferably 20 mol%, particularly preferably 25 mol%. The upper limit of the content ratio is preferably 90 mol%, more preferably 80 mol%, further preferably 70 mol%, and particularly preferably 60 mol%. By setting the content ratio of the structural unit (a1) in the above range, the radiation-sensitive resin composition can further improve resist properties such as sensitivity and resolution.

If it is desired to directly radically polymerize a monomer having a phenolic hydroxyl group such as hydroxystyrene, the polymerization may be hindered by the influence of the phenolic hydroxyl group. In this case, the polymerization is carried out in a state where the phenolic hydroxyl group is protected by a protective group such as an alkali-dissociable group, followed by hydrolysis and deprotection, whereby the structural unit (a1) can be obtained. The structural unit that provides the structural unit (a1) by hydrolysis is preferably represented by the following formula (1).

[化3]

In the formula (1), R ¹¹ is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R ¹² is a monovalent hydrocarbon group or alkoxy group having 1 to 20 carbon atoms. Examples of the monovalent hydrocarbon group having 1 to 20 carbons for R ^{12 include monovalent hydrocarbon groups having 1 to 20 carbons.} As an alkoxy group, a methoxy group, an ethoxy group, a tert-butoxy group, etc. are mentioned, for example.

As said R ¹² , an alkyl group and an alkoxy group are preferable, and a methyl group and a tertiary butoxy group are more preferable.

[Structural unit (a2)] The structural unit (a2) is a base whose solubility is changed by EUV or electron beam (EB) exposure in the absence of a radiation-sensitive acid generator, and by The radicals dissociated by EUV or electron beam (EB) exposure.

In the present invention, the term "in the absence of a radiation-sensitive acid generator" refers to a situation where there is no or substantially no radiation-sensitive acid generator. As the structural unit (a2), for example, a structural unit having a tertiary alkyl ester moiety, a structural unit having a structure in which a hydrogen atom of a phenolic hydroxyl group is substituted with a tertiary alkyl group, a structural unit having an acetal bond, etc. From the viewpoint of improving the pattern formability of the radiation-sensitive resin composition, the structural unit represented by the following formula (2) (hereinafter, also referred to as "structural unit (a2-1)") is preferred .

The structural unit exemplified in the previous paragraph is a structure widely known as an acid-dissociable group in this technical field. In addition, in the present invention, the "acid dissociable group" refers to a group that substitutes a hydrogen atom possessed by a carboxyl group, a phenolic hydroxyl group, an alcoholic hydroxyl group, a sulfo group, etc., and has the ability to be dissociated by the action of an acid. The nature of the base. As described above, in the present invention, it is not necessary to cause dissociation or solubility change such as the detachment of the structural unit (a2) due to the presence of an acid during the exposure step, or the acid generated by the self-induced radioactive acid generator through exposure. . The radiation-sensitive resin composition has a structural unit (a2) in the resin, and thus has excellent pattern formability.

[化4]

In the formula (2), R ⁷ is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R ⁸ is a hydrogen atom or a monovalent hydrocarbon group having 1 to 20 carbons. R ⁹ and R ¹⁰ are each independently a monovalent chain hydrocarbon group of 1 to 20 carbons substituted with or not substituted with a fluorine atom, or a monovalent chain hydrocarbon group of 3 to 20 carbons substituted with or not substituted with a fluorine atom A valent alicyclic hydrocarbon group, or a monovalent aromatic hydrocarbon group with 5 to 20 carbons, or a fluorine atom substituted or unsubstituted fluorine atom substituted by the combination of these groups and the bonded carbon atoms A divalent alicyclic group having 3 to 20 carbon atoms. In addition, ^{any one of R 8} to R ¹⁰ and/or the alicyclic group when the alicyclic group is present may have an unsaturated bond. In addition, the case where a plurality of any one of ^{R 8} to R ^{10 forms one alicyclic structure together is also included.}

As said R ⁷ , from the viewpoint of providing the copolymerizability of the monomer of the structural unit (a2-1), a hydrogen atom and a methyl group are preferable, and a methyl group is more preferable.

Examples of the monovalent hydrocarbon group having 1 to 20 carbons represented by R ⁸ include chain hydrocarbon groups having 1 to 10 carbons, monovalent alicyclic hydrocarbon groups having 3 to 20 carbons, and 6 to 20 carbons. The monovalent aromatic hydrocarbon group and so on.

Examples of the monovalent chain hydrocarbon group having 1 to 20 carbons represented by R ⁹ and R ¹⁰ include linear or branched saturated hydrocarbon groups having 1 to 20 carbons, or straight or branched linear or branched hydrocarbons having 1 to 20 carbons. Chain unsaturated hydrocarbon group.

Examples of the monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms represented by R ⁹ and R ¹⁰ include a monocyclic or polycyclic saturated hydrocarbon group, or a monocyclic or polycyclic unsaturated hydrocarbon group. The monocyclic saturated hydrocarbon group is preferably cyclopentyl, cyclohexyl, cycloheptyl, and cyclooctyl. The polycyclic cycloalkyl group is preferably a bridged cycloalicyclic hydrocarbon group such as norbornyl group, adamantyl group, tricyclodecyl group, and tetracyclododecyl group. Furthermore, the so-called bridged cycloalicyclic hydrocarbon group refers to a polycyclic alicyclic type in which two carbon atoms that are not adjacent to each other among the carbon atoms constituting the alicyclic ring are bonded by a bonding chain containing more than one carbon atom Hydrocarbyl.

Examples of the monovalent aromatic hydrocarbon group having 5 to 20 carbon atoms represented by R ⁹ and R ¹⁰ include aryl groups such as phenyl, tolyl, xylyl, naphthyl, and anthryl; benzyl, benzene Aralkyl groups such as ethyl, naphthylmethyl, etc.

The R ^{8 is} preferably a linear or branched saturated hydrocarbon group having 1 to 10 carbons, and an alicyclic hydrocarbon group having 3 to 20 carbons.

In addition, ^{any one of R 8} to R ¹⁰ and/or the alicyclic group when the alicyclic group is present may have an unsaturated bond.

In addition, the case where a plurality of any one of ^{R 8} to R ^{10 forms one alicyclic structure together is also included.}

In the ^{case where any plurality of R 8} to R ¹⁰ are combined with each other and have at least one cyclic structure, the chain hydrocarbon group or the alicyclic hydrocarbon group is bonded to each other and constitutes together with the bonded carbon atoms As long as the divalent alicyclic group with 3 to 20 carbons is a group formed by removing two hydrogen atoms from the same carbon atom constituting the carbon ring of the monocyclic or polycyclic alicyclic hydrocarbon with the carbon number, then It is not particularly limited. It can be any one of a monocyclic hydrocarbon group and a polycyclic hydrocarbon group. As the polycyclic hydrocarbon group, it can be any one of a bridged ring alicyclic hydrocarbon group and a condensed alicyclic hydrocarbon group, and it can also be any of a saturated hydrocarbon group and an unsaturated hydrocarbon group. A sort of. In addition, the term “condensed alicyclic hydrocarbon group” refers to a polycyclic alicyclic hydrocarbon group constituted in a form where a plurality of alicyclic rings share an edge (a bond between two adjacent carbon atoms).

In the monocyclic alicyclic hydrocarbon group, the saturated hydrocarbon group is preferably cyclopentanediyl, cyclohexanediyl, cycloheptanediyl, cyclooctanediyl, etc., and the unsaturated hydrocarbon group is preferably cyclic Pentenediyl, cyclohexenediyl, cycloheptenediyl, cyclooctenediyl, cyclodecenediyl, etc. The polycyclic alicyclic hydrocarbon group is preferably a bridged cyclic alicyclic saturated hydrocarbon group, for example, bicyclo[2.2.1]heptane-2,2-diyl (norbornane-2,2-diyl ), bicyclo[2.2.2]octane-2,2-diyl, tricyclo[3.3.1.1 ^3,7 ]decane-2,2-diyl (adamantane-2,2-diyl), etc.

Examples of the divalent linking group represented by L ¹ include: alkanediyl, cycloalkanediyl, alkenediyl, *-R ^LA O-, *-R ^LB COO-, etc. (* represents oxygen-side Bonding key). Part or all of the hydrogen atoms in these groups may be substituted with halogen atoms such as fluorine atoms or chlorine atoms, cyano groups, and the like.

As said alkanediyl group, a C1-C8 alkanediyl group is preferable.

Examples of the cycloalkanediyl group include monocyclic cycloalkanediyl groups such as cyclopentanediyl and cyclohexanediyl; and polycyclic cycloalkanediyl groups such as norbornanediyl and adamantanediyl. Wait. The cycloalkanediyl group is preferably a cycloalkanediyl group having 5 to 12 carbon atoms.

As said alkene diyl group, an ethylene diyl group, a propylene diyl group, a butene diyl group, etc. are mentioned, for example. The alkenediyl group is preferably an alkenediyl group having 2 to 6 carbon atoms.

Examples of R ^{LA of} the *-R ^LA O- include the alkanediyl group, the cycloalkanediyl group, the alkenediyl group, and the like. Examples of R ^{LB of} *-R ^LB COO- include the alkanediyl group, the cycloalkanediyl group, the alkenediyl group, and the aryldiyl group. As an aryldiyl group, for example, phenylene, phenylene, naphthylene, etc. may be mentioned. The aryl diyl group is preferably an aryl diyl group having 6 to 15 carbon atoms.

Among these, it is preferred that R ⁸ is an alkyl group having 1 to 4 carbons, ^{and the alicyclic structure formed by R 9} and R ¹⁰ combined with each other and the carbon atoms to which they are bonded is a polycyclic or monocyclic ring Alkane structure. L ^{1 is} preferably a single bond or *-R ^LA O-. As R ^LA , an alkanediyl group is preferred.

In addition, as the structural unit (a2-1), for example, structural units represented by the following formulas (2-1) to (2-6) (hereinafter, also referred to as "structural unit (a2-1- 1) ~ Structural unit (a2-1-6)”) and so on.

[化6]

[化5]

[化6]

In the above formulas (a2-1-1) to (a2-1-6), R ⁷ to R ¹⁰ are the same as the above formula (2). i and j are each independently an integer of 1-4. In addition, the cycloalkyl ring in the formula (a2-1-3) may be substituted with a halogen atom.

In the above formulas (a2-1-5) to (a2-1-6), n _A is 0 or 1.

As i and j, 1 is preferable. R ⁸ to R ^{10 are} preferably methyl, ethyl, isopropyl, tertiary butyl or phenyl.

In addition, as the structural unit (a2-1), structural units represented by the following formulas (2-7) to (2-8) (hereinafter, also referred to as "structural unit (a2-1- 7) ~ Structural unit (a2-1-8)”) and so on.

[化7]

In the formulas (2-7) to (2-8), R ^{αf is} each independently a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R ^{βf is} each independently a hydrogen atom or a chain alkyl group having 1 to 5 carbon atoms. h ₁ is an integer of 1-4.

The R ^{βf is} preferably a hydrogen atom, a methyl group, or an ethyl group. As h ₁ , 1 or 2 is preferable.

In addition, a plurality of R ^βf may form an alicyclic structure together. For example, two R ^βf together form a cyclohexane structure or a benzene ring structure.

As the structural unit (a2-1), among these, the structural unit (a2-1-1), the structural unit (a2-1-2), the structural unit (a2-1-3), and the structural unit (a2 -1-4), structural unit (a2-1-7), more preferably structural unit with 1-alkylcycloalkyl, structural unit with 1-arylcycloalkyl, structural unit with cycloalkenyl , The structural unit with 1-alkyladamantyl, the structural unit with arylalkyl, the structural unit with substituted or unsubstituted cycloalkylalkyl.

The resin (A0) may contain one kind or a combination of two or more kinds of structural units (a2).

The lower limit of the content ratio of the structural unit (a2) is preferably 10 mol%, more preferably 15 mol%, and still more preferably 20 mol% with respect to all the structural units constituting the resin (A0) as the base resin %, particularly preferably 30 mol%. The upper limit of the content ratio is preferably 90 mol%, more preferably 80 mol%, further preferably 75 mol%, particularly preferably 70 mol%. By setting the content ratio of the structural unit (a2) in the above range, the pattern formability of the radiation-sensitive resin composition can be further improved.

[Structural unit (a3)] The structural unit (a3) is a structural unit containing a lactone structure, a cyclic carbonate structure, a sultone structure, or a combination of these. The resin (A0) has a structural unit (a3) in addition to the structural unit (a1) and the structural unit (a2), whereby the polarity can be moderated. As a result, the radiation-sensitive resin composition can form a finer resist pattern with excellent rectangular cross-sectional shape as a chemically amplified resist material. Here, the lactone structure refers to a structure having one ring (lactone ring) including a group represented by -OC(O)-. In addition, the cyclic carbonate structure refers to a structure having one ring (cyclic carbonate ring) including a group represented by -OC(O)-O-. The sultone structure refers to a structure having one ring (sultone ring) including a group represented by _{-OS(O) 2 -.}

As a structural unit (a3), the structural unit etc. which are represented by the following formula, for example are mentioned.

[化8]

[化9]

[化10]

[化11]

In the formula, R ^AL is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group.

As said R ^AL , from the viewpoint of providing the copolymerizability of the monomer of the structural unit (a3), a hydrogen atom and a methyl group are preferable, and a methyl group is more preferable.

As the structural unit (a3), among these, a structural unit containing a norbornane lactone structure, a structural unit containing an oxanorbornane lactone structure, a structural unit containing a γ-butyrolactone structure, and The structural unit of the ethylene carbonate structure, and the structural unit containing the norbornane sultone structure, more preferably the structural unit derived from (meth)acrylate norbornane lactone-based ester, derived from (methyl) The structural unit of oxanorbornane lactone-based acrylate, a structural unit derived from cyano-substituted norbornane lactone-based (meth)acrylate, and a structural unit derived from norbornane (meth)acrylate The structural unit of ester-oxycarbonyl methyl ester, the structural unit derived from (meth)acrylate butyrolactone-3-yl ester, the structural unit derived from (meth)acrylate butyrolactone-4-yl ester, Structural unit derived from (meth)acrylic acid-3,5-dimethylbutyrolactone-3-yl ester, derived from (meth)acrylic acid-4,5-dimethylbutyrolactone-4-yl ester The structural unit, derived from (meth)acrylate-1-(butyrolactone-3-yl)cyclohexane-1-yl ester, derived from (meth)acrylate ethylene carbonate-methyl ester The structural unit, the structural unit derived from (meth) acrylate cyclohexene carbonate-based methyl ester, the structural unit derived from (meth) acrylate norbornane sultone-based ester, and the structural unit derived from (methyl) ) The structural unit of acrylate-norbornane sultone-oxycarbonyl methyl ester.

When the resin (A0) has a structural unit (a3), the lower limit of the content ratio of the structural unit (a3) to all the structural units constituting the resin (A0) is preferably 1 mol%, more preferably 10 Mole%, further preferably 20 mole%, particularly preferably 25 mole%. On the other hand, the upper limit of the content ratio is preferably 70 mol%, more preferably 65 mol%, still more preferably 60 mol%, and particularly preferably 55 mol%. By setting the content ratio in the above range, a finer resist pattern with excellent rectangular cross-sectional shape can be formed.

[Structural unit (a4)] The resin (A0) may suitably have another structural unit (also referred to as a structural unit (a4)) other than the structural unit (a1) to the structural unit (a3). As a structural unit (a4), the structural unit etc. which have a fluorine atom, an alcoholic hydroxyl group, a carboxyl group, a cyano group, a nitro group, a sulfonamide group, etc. are mentioned, for example. Among these, a structural unit having a fluorine atom, a structural unit having an alcoholic hydroxyl group, and a structural unit having a carboxyl group are preferable, and a structural unit having a fluorine atom and a structural unit having an alcoholic hydroxyl group are more preferable.

When the resin (A0) has a structural unit (a4), the lower limit of the content ratio of the structural unit (a4) to all the structural units constituting the resin (A0) is preferably 1 mol%, more preferably 5 Mole%, and more preferably 10 mole%. On the other hand, the upper limit of the content ratio is preferably 50 mol%, more preferably 40 mol%, and still more preferably 30 mol%. By setting the content ratio of the other structural unit in the above range, the solubility of the resin (A0) in the developer can be more moderate. If the content ratio of other structural units exceeds the upper limit, the pattern formability may decrease.

In addition, in the resin (A0) of the present invention, for example, (i) a repeating structure of hydroxystyrene obtained by polymerizing a hydroxystyrene monomer protected by an alkali-hydrolyzable group and then hydrolyzing it, and (ii) Any repeating structure obtained by directly polymerizing a hydroxystyrene monomer can correspond to the structural unit (a1). In addition, (iii) a repeating structure obtained by polymerizing a hydroxystyrene monomer protecting a hydroxyl group by a group dissociated by EUV or electron beam (EB) exposure may correspond to the aforementioned "structural unit (a2)".

The content of the resin (A0) is usually 85% by mass or more in the total solid content of the radiation-sensitive resin composition. Among them, it is preferably 95% by mass or more, more preferably 99% by mass or more, still more preferably 99.9% by mass or more, and particularly preferably 99.99% by mass or more. Here, the "solid content" refers to all components other than the (B) solvent among the components contained in the radiation-sensitive resin composition.

(Synthesis method of resin (A0)) The resin (A0) as the base resin can be synthesized, for example, by using a radical polymerization initiator or the like, and polymerizing monomers that provide each structural unit in an appropriate solvent.

Examples of the radical polymerization initiator include: azobisisobutyronitrile (AIBN), 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile) , 2,2'-azobis(2-cyclopropylpropionitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobisisobutyric acid Azo radical initiators such as dimethyl; peroxide radical initiators such as benzyl peroxide, tert-butyl hydroperoxide, cumene hydroperoxide, etc. Among these, AIBN, dimethyl 2,2'-azobisisobutyrate are preferred, and AIBN is more preferred. These radical initiators can be used alone or in combination of two or more.

Examples of the solvent used in the polymerization reaction include alkanes such as n-pentane, n-hexane, n-heptane, n-octane, n-nonane, and n-decane; cyclohexane, cycloheptane, and cyclohexane. Cycloalkanes such as octane, decahydronaphthalene, norbornane; aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene, cumene, etc.; chlorobutane, bromohexane, dichloroethane, Halogenated hydrocarbons such as hexamethylene dibromide and chlorobenzene; saturated carboxylic acid esters such as ethyl acetate, n-butyl acetate, isobutyl acetate, and methyl propionate; acetone, methyl ethyl ketone , 4-methyl-2-pentanone, 2-heptanone and other ketones; tetrahydrofuran, dimethoxyethane, diethoxyethane and other ethers; methanol, ethanol, 1-propanol, 2 -Alcohols such as propanol and 4-methyl-2-pentanol. These solvents used in the polymerization reaction may be used singly or in combination of two or more kinds.

The reaction temperature in the polymerization reaction is usually 40°C to 150°C, preferably 50°C to 120°C. The reaction time is usually 1 hour to 48 hours, preferably 1 hour to 24 hours.

The molecular weight of the resin (A0) as the base resin is not particularly limited. The polystyrene-converted weight average molecular weight (Mw) obtained by gel permeation chromatography (GPC) is preferably 1,000 or more and 50,000 Below, more preferably 2,000 or more and 30,000 or less, still more preferably 3,000 or more and 15,000 or less, and particularly preferably 4,000 or more and 12,000 or less. If the Mw of the resin (A0) is less than the lower limit, the heat resistance of the obtained resist film may decrease. If the Mw of the resin (A0) exceeds the upper limit, the developability of the resist film may decrease.

The ratio (Mw/Mn) of the resin (A0) as the base resin of the Mw obtained by GPC to the polystyrene-converted number average molecular weight (Mn) is usually 1 or more and 5 or less, preferably 1 or more and 3 Below, it is more preferable that it is 1 or more and 2 or less.

The Mw and Mn of the resin in this specification are values measured using gel permeation chromatography (GPC) based on the following conditions. GPC column: 2 G2000HXL, 1 G3000HXL, 1 G4000HXL (the above are manufactured by Tosoh) Column temperature: 40℃ Dissolution solvent: tetrahydrofuran Flow rate: 1.0 mL/min Sample concentration: 1.0% by mass Sample injection volume: 100 μL Detector: Differential refractometer Standard material: monodisperse polystyrene

(Other resins) The radiation-sensitive resin composition of the present embodiment may also include a resin having a higher mass content of fluorine atoms than the base resin (hereinafter, also referred to as "high fluorine content resin") as another resin. When the radiation-sensitive resin composition contains a resin with a high fluorine content, it can be present on the surface layer of the resist film rather than the base resin. As a result, the state or resistance of the resist film surface can be improved. The composition distribution in the etchant film is controlled to a desired state.

As a high fluorine content resin, it is preferable to have, for example, a structural unit represented by the following formula (3) (hereinafter, also referred to as "structural unit (a5)"). [化12]

In the formula (3), R ¹³ is a hydrogen atom, a methyl group, or a trifluoromethyl group. G is a single bond, an oxygen atom, a sulfur atom, -COO-, -SO ₂ ONH-, -CONH- or -OCONH-. R ¹⁴ is a monovalent fluorinated chain hydrocarbon group having 1 to 20 carbons or a monovalent fluorinated alicyclic hydrocarbon group having 3 to 20 carbons.

As said R ¹³ , from the viewpoint of providing the copolymerizability of the monomer of the structural unit (a5), a hydrogen atom and a methyl group are preferable, and a methyl group is more preferable.

As said G ^L , from the viewpoint of providing the copolymerizability of the monomer of the structural unit (a5), a single bond and -COO- are preferred, and -COO- is more preferred.

Examples of the monovalent fluorinated chain hydrocarbon group having 1 to 20 carbons represented by R ¹⁴ include that a part or all of the hydrogen atoms of the straight or branched chain alkyl group having 1 to 20 carbons are substituted with fluorine atoms. Become.

Examples of the monovalent fluorinated alicyclic hydrocarbon group having 3 to 20 carbons represented by R ¹⁴ include part or all of the hydrogen atoms of the monocyclic or polycyclic hydrocarbon group having 3 to 20 carbons via fluorine atoms. Replaced by.

The R ^{14 is} preferably a fluorinated chain hydrocarbon group, more preferably a fluorinated alkyl group, and still more preferably 2,2,2-trifluoroethyl, 1,1,1,3,3,3-hexa Fluoropropyl and 5,5,5-trifluoro-1,1-diethylpentyl.

When the high fluorine content resin has the structural unit (a5), the lower limit of the content ratio of the structural unit (a5) is preferably 10 mol%, more preferably 15 relative to all the structural units constituting the high fluorine content resin. mol%, more preferably 20 mol%, particularly preferably 25 mol%. The upper limit of the content ratio is preferably 60 mol%, more preferably 50 mol%, and still more preferably 40 mol%. By setting the content ratio of the structural unit (a5) in the above range, the mass content of fluorine atoms in the high fluorine content resin can be adjusted more appropriately, and the presence of a bias in the surface layer of the resist film can be further promoted.

The high fluorine content resin may have a fluorine atom-containing structural unit represented by the following formula (f-1) (hereinafter, also referred to as a structural unit (a6)) in addition to the structural unit (a5). The high fluorine content resin has the structural unit (f-1), which can improve the solubility to the alkaline developer and suppress the development of defects. [化13]

The structural unit (a6) is roughly divided into a case having (x) an alkali-soluble group and a group having (y) that is dissociated by the action of an alkali and has increased solubility in an alkaline developer (hereinafter, also abbreviated as "alkali Dissociative basis") in these two cases. Both (x) and (y) are common. In the formula (f-2), R ^C is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R ^D is a single bond, the carbon number (s + 1) valent hydrocarbon group having 1 to 20, in the terminal bond of the hydrocarbon group R ^E side of the junction oxygen atom, a sulfur atom, -NR ^dd -, carbonyl, -COO- Or a structure formed of -CONH-, or a structure formed by substituting a part of the hydrogen atoms of the hydrocarbon group with an organic group having a heteroatom. R ^dd is a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms. s is an integer of 1-3.

When the structural unit (a6) has (x) an alkali-soluble group, R ^F is a hydrogen atom, and A ¹ is an oxygen atom, -COO-* or -SO ₂ O-*. * Indicates the position bonded to R ^F. W ¹ is a single bond, a hydrocarbon group having 1 to 20 carbon atoms, or a divalent fluorinated hydrocarbon group. When A ¹ is an oxygen atom, W ¹ is a fluorinated hydrocarbon group having a fluorine atom or a fluoroalkyl group on the carbon atom to which ^{A 1 is bonded. RE} is a single bond or a divalent organic group having 1 to 20 carbons. When s is 2 or 3, a plurality of R ^E , W ¹ , A ¹ and R ^F may be the same or different. Since the structural unit (a6) has an alkali-soluble group (x), the affinity for an alkaline developer can be improved and development defects can be suppressed. As the structural unit (a6) having (x) an alkali-soluble group, it is particularly preferred that A ¹ is an oxygen atom and W ¹ is 1,1,1,3,3,3-hexafluoro-2,2-methanediyl Condition.

When the structural unit (a6) has (y) a base dissociable group, R ^F is a monovalent organic group with 1 to 30 carbon ^{atoms, and A 1} is an oxygen atom, -NR ^aa -, -COO-* or -SO ₂ O-*. R ^aa is a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms. * Indicates the position bonded to R ^F. W ¹ is a single bond or a divalent fluorinated hydrocarbon group having 1 to 20 carbons. ^RE is a single bond or a divalent organic group having 1 to 20 carbons. When A ¹ is -COO-* or -SO ₂ O-*, W ¹ or R ^F has a fluorine atom on the carbon atom bonded to A ^{1 or a carbon atom adjacent to it.} R ^E side terminal bond in the case where A ¹ is an oxygen atom, W ^1, R ^E is a single bond, R ^D is a hydrocarbon group having 1 to to 20 have a junction structure formed by a carbonyl group, R ^F is a fluorine The organic group of the atom. When s is 2 or 3, a plurality of R ^E , W ¹ , A ¹ and R ^F may be the same or different. Since the structural unit (a6) has (y) an alkali dissociable group, in the alkali development step, the surface of the resist film changes from hydrophobic to hydrophilic. As a result, the affinity for the developer can be greatly improved, and development defects can be suppressed more efficiently. As the structural unit (a6) having (y) a base dissociable group, it is particularly preferable that A ¹ is -COO-* and R ^F or W ¹ or both of them have a fluorine atom.

R ^C is preferably a hydrogen atom and a methyl group, and more preferably a methyl group, from the viewpoint of providing the copolymerizability of the monomer of the structural unit (a6) and the like.

When ^RE is a divalent organic group, it is preferably a group having a lactone structure, more preferably a group having a polycyclic lactone structure, and still more preferably a group having a norbornane lactone structure.

When the high fluorine content resin has the structural unit (a6), the lower limit of the content ratio of the structural unit (a6) is preferably 10 mol%, more preferably 20 relative to all the structural units constituting the high fluorine content resin. mol%, more preferably 30 mol%, particularly preferably 35 mol%. The upper limit of the content ratio is preferably 90 mol%, more preferably 75 mol%, and still more preferably 60 mol%. By setting the content ratio of the structural unit (a6) in the above range, the water repellency of the resist film at the time of liquid immersion exposure can be further improved.

The lower limit of Mw of the high fluorine content resin is preferably 1,000, more preferably 2,000, still more preferably 3,000, and particularly preferably 5,000. The upper limit of the Mw is preferably 50,000, more preferably 30,000, still more preferably 20,000, and particularly preferably 15,000.

The lower limit of Mw/Mn of the high fluorine content resin is usually 1, and more preferably 1.1. As the upper limit of the Mw/Mn, it is usually 5, preferably 3, more preferably 2, and still more preferably 1.7.

As the lower limit of the content of the high fluorine content resin, relative to the total solid content in the radiation-sensitive resin composition, it is preferably 0.1% by mass, more preferably 0.5% by mass, still more preferably 1% by mass, and particularly preferably 1.5% by mass. The upper limit of the content is preferably 20% by mass, more preferably 15% by mass, still more preferably 10% by mass, and particularly preferably 7% by mass.

As the lower limit of the content of the high fluorine content resin, relative to 100 parts by mass of the base resin, it is preferably 0.1 parts by mass, more preferably 0.5 parts by mass, still more preferably 1 part by mass, particularly preferably 1.5 parts by mass. The upper limit of the content is preferably 15 parts by mass, more preferably 10 parts by mass, still more preferably 8 parts by mass, particularly preferably 5 parts by mass.

By setting the content of the high fluorine content resin within the above range, the high fluorine content resin can be more effectively concentrated on the surface layer of the resist film. As a result, the resist film performance during liquid immersion exposure can be further improved. Water repellency of the surface. The radiation-sensitive resin composition may contain one or two or more resins with high fluorine content.

(Synthetic method of high fluorine content resin) The high fluorine content resin can be synthesized by the same method as the synthesis method of the base resin.

((B) Solvent) The radiation-sensitive resin composition contains a solvent. The solvent is not particularly limited as long as it is a solvent that can dissolve or disperse the resin, the radiation-sensitive acid generator, and optionally contained optional components.

Examples of the solvent include alcohol-based solvents, ether-based solvents, ketone-based solvents, amide-based solvents, ester-based solvents, and hydrocarbon-based solvents.

As the alcohol solvent, for example: Isopropanol, 4-methyl-2-pentanol, 3-methoxybutanol, n-hexanol, 2-ethylhexanol, furfuryl alcohol, cyclohexanol, 3,3,5-trimethylcyclohexanol , Diacetone alcohol and other monohydric alcohol solvents with 1 to 18 carbon atoms; Ethylene glycol, 1,2-propanediol, 2-methyl-2,4-pentanediol, 2,5-hexanediol, diethylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol, etc. Carbon number 2 ～18 polyol solvents; A partial polyol ether solvent etc. which are obtained by etherifying a part of the hydroxyl group which the said polyol solvent has.

As ether solvents, for example: Dialkyl ether solvents such as diethyl ether, dipropyl ether, and dibutyl ether; Cyclic ether solvents such as tetrahydrofuran and tetrahydropyran; Ether solvents containing aromatic rings such as diphenyl ether and anisole (methyl phenyl ether); A polyhydric alcohol ether solvent etc. which are obtained by etherifying the hydroxyl group which the said polyhydric alcohol solvent has.

Examples of ketone solvents include chain ketone solvents such as acetone, methyl ethyl ketone, and methyl-isobutyl ketone; Cyclic ketone solvents such as cyclopentanone, cyclohexanone and methylcyclohexanone; 2,4-Pentanedione, acetonylacetone, acetophenone, etc.

Examples of amide-based solvents include cyclic amide-based solvents such as N,N'-dimethylimidazolidone and N-methylpyrrolidone; N-methylformamide, N,N-dimethylformamide, N,N-diethylformamide, acetamide, N-methylacetamide, N,N-dimethylethyl Chain amide-based solvents such as amide and N-methyl propanamide.

As the ester-based solvent, for example: Monocarboxylic acid ester solvents such as n-butyl acetate and ethyl lactate; Polyol partial ether acetate solvents such as diethylene glycol mono-n-butyl ether acetate, propylene glycol monomethyl ether acetate, and dipropylene glycol monomethyl ether acetate; Lactone solvents such as γ-butyrolactone and valerolactone; Carbonate-based solvents such as diethyl carbonate, ethylene carbonate, and propylene carbonate; Polycarboxylic acid diester-based solvents such as propylene glycol diacetate, methoxytriethylene glycol acetate, diethyl oxalate, ethyl acetate, ethyl lactate, and diethyl phthalate.

As the hydrocarbon solvent, for example: Aliphatic hydrocarbon solvents such as n-hexane, cyclohexane and methylcyclohexane; Aromatic hydrocarbon solvents such as benzene, toluene, diisopropylbenzene, n-pentylnaphthalene, etc.

Among these, ester-based solvents and ketone-based solvents are preferred, polyol partial ether acetate solvents, cyclic ketone-based solvents, and lactone-based solvents are more preferred, and propylene glycol monomethyl ether acetate, Cyclohexanone, γ-butyrolactone. The radiation-sensitive resin composition may also contain one or two or more solvents.

((C) Radiation-sensitive acid generator) The radiation-sensitive resin composition of the present invention may also contain a radiation-sensitive acid generator. (C) The radiation-sensitive acid generator is preferably an onium salt compound, and more preferably a sulfonium salt compound and an iodonium salt. As such an onium salt compound, a known compound can be used.

In addition, in the present invention, when the (C) radiation-sensitive acid generator is contained in the (A) radiation-sensitive resin composition, it is desirable that (C) the radiation-sensitive acid generator is small, and the following examples are listed Example: In the (A) radiation-sensitive resin composition, for example, the (C) radiation-sensitive acid generator is preferably 0.1% by mass or less, more preferably 0.05% by mass or less, more preferably 0.01% by mass or less. On the other hand, as the lower limit of the compounding amount, for example, 0.0001% by mass and 0.00001% by mass can be cited, and it is desirable that the (C) radiosensitive acid generator (0% by mass) is not contained.

As described above, in the present invention, it is not necessary to cause dissociation or solubility change such as the detachment of the structural unit (a2) due to the presence of an acid during the exposure step, or the acid generated by the self-induced radioactive acid generator through exposure. . In addition, the radiation-sensitive resin composition or resist film of the present invention does not contain or substantially does not contain (C) a radiation-sensitive acid generator, thereby simplifying the composition of the resist film and improving uniformity. The adverse effects on the boundary surface of the exposed part and the unexposed part caused by the acid generated during the exposure step are suppressed. As a result, the performance of the resist can be improved more reliably. Therefore, it is particularly desirable that the (C) radiation-sensitive acid generator is not contained or substantially not present in the radiation-sensitive resin composition or resist film of the present invention.

(Other optional ingredients) The radiation-sensitive resin composition may contain other optional components in addition to the above-mentioned components. Examples of the other optional components include acid diffusion control agents, cross-linking agents, localization accelerators, surfactants, compounds containing alicyclic skeletons, sensitizers, and the like. These other arbitrary components can be used individually by 1 type or in combination of 2 or more types.

((D) Acid diffusion control agent) The said radiation sensitive resin composition may contain an acid diffusion control agent as needed. The acid diffusion control agent exerts the effect of controlling the diffusion phenomenon of the acid generated by the self-induced radioactive acid generator in the resist film by exposure, and suppressing the poor chemical reaction in the non-exposed area. In addition, the storage stability of the obtained radiation-sensitive resin composition is improved. Furthermore, the resolution of the resist pattern is further improved, and the line width change of the resist pattern caused by the variation in the standing time from exposure to development can be suppressed, so that radiation sensitivity with excellent process stability can be obtained. Resin composition.

(Crosslinking agent) The cross-linking agent is a compound having two or more functional groups. In the baking step after the general exposure step, the acid catalyst reaction causes a cross-linking reaction in the polymer component to increase the molecular weight of the polymer component. Thereby, the solubility of the pattern exposure part to the developer is reduced. As said functional group, (meth)acryloyl group, a hydroxymethyl group, an alkoxymethyl group, an epoxy group, a vinyl ether group, etc. are mentioned, for example.

(Preferred to existence accelerator) The partial existence accelerator is one having the effect of making the high fluorine content resin more efficiently partial and existing on the surface of the resist film. By making the radiation-sensitive resin composition contain the deflection-existence accelerator, the addition amount of the high fluorine content resin can be reduced compared to the previous one. Therefore, while maintaining the lithography performance of the radiation-sensitive resin composition, the elution of the components from the resist film to the liquid immersion medium is further suppressed, or the liquid immersion exposure can be performed at a higher speed by high-speed scanning, as a result , It is possible to improve the hydrophobicity of the resist film surface that suppresses defects caused by liquid immersion, such as watermark defects. Examples of those that can be used as such a biased presence accelerator include low-molecular compounds having a relative permittivity of 30 or more and 200 or less and a boiling point of 100° C. or more under one atmosphere. As such a compound, specifically, a lactone compound, a carbonate compound, a nitrile compound, a polyhydric alcohol, etc. are mentioned.

(Interface active agent) The surfactant has the effect of improving coatability, striation, developability, and the like. As surfactants, for example, polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene n-octyl phenyl ether, polyoxyethylene n-nonyl phenyl ether, polyoxyethylene stearyl ether, polyoxyethylene Non-ionic surfactants such as ethylene glycol dilaurate and polyethylene glycol distearate; commercially available products include: KP341 (manufactured by Shin-Etsu Chemical Industry), Polyflow No. 75. Polyflow No. 95 (the above are manufactured by Kyoeisha Chemicals), Eftop EF301, Eftop EF303, Eftop EF352 (the above are made by Taokai Tohchem Products, Megafac F171, Megafac F173 (manufactured by DIC), Fluorad FC430, Fluorad FC431 (above Manufactured by Sumitomo 3M), Asahi Guard AG710, Surflon S-382, Surflon SC-101, Surflon SC-102, Surflon ) SC-103, Surflon SC-104, Surflon SC-105, Surflon SC-106 (manufactured by Asahi Glass Industry), etc. The content of the surfactant in the radiation-sensitive resin composition is usually 2 parts by mass or less with respect to 100 parts by mass of the resin.

(Compounds containing alicyclic skeleton) The compound containing an alicyclic skeleton has an effect of improving dry etching resistance, pattern shape, adhesion to a substrate, and the like.

As the compound containing an alicyclic skeleton, for example: 1-adamantane carboxylic acid, 2-adamantanone, 1-adamantane carboxylic acid tert-butyl ester and other adamantane derivatives; Deoxycholic acid tert-butyl ester, deoxycholic acid tert-butoxycarbonyl methyl ester, deoxycholic acid 2-ethoxyethyl ester and other deoxycholic acid esters; Lithocholic acid esters such as tertiary butyl lithocholic acid, tertiary butoxycarbonyl methyl lithocholic acid, 2-ethoxyethyl lithocholic acid; 3-[2-hydroxy-2,2-bis(trifluoromethyl)ethyl]tetracyclo[4.4.0.1(2,5).1(7,10)]dodecane, 2-hydroxy-9- Methoxycarbonyl-5-oxo-4-oxa-tricyclo[4.2.1.0(3,7)]nonane and the like. The content of the alicyclic skeleton-containing compound in the radiation-sensitive resin composition is usually 5 parts by mass or less with respect to 100 parts by mass of the resin.

(Sensitizer) The sensitizer has an effect of increasing the amount of acid derived from a radiation-sensitive acid generator or the like, and has an effect of improving the "apparent sensitivity" of the radiation-sensitive resin composition.

Examples of sensitizers include carbazoles, acetophenones, benzophenones, naphthalenes, phenols, biacetin, eosin, rose bengal, pyrenes, anthracenes, and phenothiazines. Class etc. These sensitizers may be used alone, or two or more of them may be used in combination. The content of the sensitizer in the radiation-sensitive resin composition is usually 2 parts by mass or less with respect to 100 parts by mass of the resin.

＜Preparation method of radiation-sensitive resin composition＞ The (A) radiation-sensitive resin composition can be prepared, for example, by mixing the resin (A0) and the (B) solvent and other components as necessary in a predetermined ratio. The radiation-sensitive resin composition is preferably mixed, and then filtered with a filter having a pore size of about 0.05 μm, for example. The solid content concentration of the radiation-sensitive resin composition is usually 0.1% by mass to 50% by mass, preferably 0.5% by mass to 30% by mass, and more preferably 1% by mass to 20% by mass.

<Method of forming resist pattern> The resist pattern forming method of the present invention includes: Step (1) (hereinafter, also referred to as "resist film formation step"), forming (C) a resist film with a radiation-sensitive acid generator content of 0.1% by mass or less; Step (2) (hereinafter, also referred to as "exposure step"), performing EUV or electron beam (EB) exposure on the resist film; and In step (3) (hereinafter, also referred to as "development step"), the resist film exposed in the step (2) is developed.

According to the resist pattern forming method, since (C) a resist film or the like having a radiation-sensitive acid generator content of 0.1% by mass or less formed using the radiation-sensitive resin composition or the like is used, It is possible to form a resist pattern that can exhibit sensitivity or resolution in the exposure step at an excellent level. Hereinafter, each step will be described.

[Resist Film Formation Step] In this step (the step (1)), a resist film is formed from the radiation-sensitive resin composition or the like. Examples of the substrate on which the resist film is formed include conventionally known ones such as silicon wafers, silicon dioxide, and aluminum-coated wafers. In addition, an organic or inorganic antireflection film disclosed in, for example, Japanese Patent Publication No. 6-12452 or Japanese Patent Application Publication No. 59-93448 may be formed on the substrate. Examples of the coating method include spin coating (spin coating), cast coating, roll coating, and the like. After coating, prebake (PB) may be carried out if necessary to volatilize the solvent in the coating film. The PB temperature is usually 60°C to 140°C, preferably 80°C to 120°C. The PB time is usually 5 seconds to 600 seconds, preferably 10 seconds to 300 seconds. The thickness of the resist film to be formed is preferably 10 nm to 1,000 nm, and more preferably 10 nm to 500 nm.

In the case of liquid immersion exposure, regardless of the presence or absence of water-repellent polymer additives such as the high fluorine content resin in the radiation-sensitive resin composition, in order to avoid direct contact between the liquid immersion medium and the resist film For the purpose of the above, a protective film for liquid immersion that is insoluble to the liquid immersion medium may also be provided on the formed resist film. As the protective film for liquid immersion, a solvent-peelable protective film that is peeled off with a solvent before the development step (for example, refer to Japanese Patent Laid-Open No. 2006-227632), and a developer-peelable type that peels off at the same time as the development in the development step can also be used. Protective film (for example, refer to WO2005-069076 and WO2006-035790). Among them, from the viewpoint of yield, it is preferable to use a protective film for developer peeling type liquid immersion.

In addition, in the case of performing the exposure step as the next step using radiation with a wavelength of 50 nm or less, it is preferable to use a resin having the structural unit (a1) and the structural unit (a2) as the basis of the composition Resin.

In addition, the step (1) is a step of forming (C) a resist film in which the content of the radiation-sensitive acid generator is 0.1% by mass or less, and a known method can be suitably used for the formation of the resist film. The resist film can be formed, for example, by using the resin (A0) or the like. More specifically, for example, the resist film may be (A) the radiation-sensitive resin composition with respect to (B) the total amount of components other than the solvent, and the (C) radiation-sensitive acid generator may be 0.1 mass The (A) radiation-sensitive resin composition of% or less is easily formed. Alternatively, for example, the resist film can be easily formed from the radiation-sensitive resin composition (A) that does not contain a radiation-sensitive acid generator.

In addition, in the resist film formed in the step (1), the content of (C) a radiation-sensitive acid generator is 0.1% by mass or less, and the resist film contains (C) a radiation-sensitive acid In the case of the generator, it is desirable that the (C) radiation-sensitive acid generator is small. For example, the following examples can be cited: In the resist film, the (C) radiation-sensitive acid generator is more preferably 0.05% by mass Below, it is more preferable that it is 0.01 mass% or less. On the other hand, as the lower limit of the compounding amount, it is desirable not to contain (C) the radioactive acid generator (0% by mass).

As described above, in the present invention, for example, it is not necessary to cause dissociation or solubility such as the detachment of the structural unit (a2) by the presence of an acid during the exposure step, or the acid generated by the self-induced radiographic acid generator by exposure. Variety. In addition, the (C) radiation-sensitive acid generator is not contained or substantially not present in the resist film of the present invention, whereby the constituent components of the resist film are simplified, thereby improving uniformity, or generation during the exposure step The adverse effects of the exposed part and the unexposed part of the boundary surface caused by the acid are suppressed. As a result, the performance of the resist can be improved more reliably. Therefore, it is particularly desirable that the (C) radiation-sensitive acid generator is not contained or substantially not contained in the resist film of the present invention.

[Exposure Step] In this step (the step (2)), the resist film formed in the step (1), the resist film formation step, is irradiated with radiation through a photomask (via a liquid immersion medium such as water as the case may be) To make an exposure. As the radiation used for exposure, depending on the line width of the target pattern, for example, EUV (extreme ultraviolet) or electron beam (EB) can be cited.

In the case of exposure by liquid immersion exposure, as the liquid immersion medium to be used, for example, water, fluorine-based inactive liquid, and the like can be cited. The liquid immersion medium is preferably a liquid that is transparent to the exposure wavelength and has a temperature coefficient of refractive index as small as possible to minimize the distortion of the optical image projected on the film. In the case of using water, additives that reduce the surface tension of water and increase the interfacial activity may be added in a slight ratio. The additive preferably does not dissolve the resist film on the wafer, and has negligible influence on the optical coating on the lower surface of the lens. As the water used, distilled water is preferred.

In the invention of the present application, after the exposure, a difference in solubility with respect to the developer occurs between the exposed part and the unexposed part. Furthermore, in the invention of the present application, since it does not contain or substantially does not contain a radioactive acid generator, it is basically not necessary after the exposure to promote the acid caused by the self-induced radioactive acid generator. The dissociation of acid-dissociable groups possessed by resins and the like is post exposure bake (PEB) for the purpose of dissociation. However, in all the embodiments of the present invention, for the purpose different from the purpose of generating acid by the self-induced radioactive acid generator after exposure, it is not excluded to perform PEB as a heat treatment. The PEB temperature of the heat treatment is, for example, 50°C to 180°C, and 80°C to 130°C is exemplified. In addition, the PEB time of the heat treatment is, for example, 5 seconds to 600 seconds, and examples thereof include 10 seconds to 300 seconds.

[Development step] In this step (the step (3)), the resist film exposed in the step (2), that is, the exposure step, is developed. Thereby, a predetermined resist pattern can be formed. Generally speaking, rinse with water or alcohol and other rinsing liquid after development and then dry.

In addition, in the step (3), in a certain embodiment, an organic solvent development can be used to form a negative pattern.

In addition, in the step (3), in a certain embodiment, an alkaline developer may be used for development to form a positive pattern.

As the developer used for the development, in the case of alkali development, for example, sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, ammonia, ethylamine, n-propyl are dissolved. Base amine, diethyl amine, di-n-propyl amine, triethyl amine, methyl diethyl amine, ethyl dimethyl amine, triethanol amine, tetramethyl ammonium hydroxide (TMAH), Pyrrole, piperidine, choline, 1,8-diazabicyclo-[5.4.0]-7-undecene, 1,5-diazabicyclo-[4.3.0]-5-nonene and other bases An alkaline aqueous solution of at least one kind of a sexual compound, etc. Among these, a TMAH aqueous solution is preferred, and a 2.38% by mass TMAH aqueous solution is more preferred.

In addition, in the case of organic solvent development, organic solvents such as hydrocarbon-based solvents, ether-based solvents, ester-based solvents, ketone-based solvents, and alcohol-based solvents, or solvents containing organic solvents can be cited. As the organic solvent, for example, one or two or more of the solvents exemplified as the solvent of the radiation-sensitive resin composition can be cited. Among these, ester-based solvents and ketone-based solvents are preferred. As the ester-based solvent, an acetate-based solvent is preferred, and n-butyl acetate and pentyl acetate are more preferred. As the ketone solvent, a chain ketone is preferred, and 2-heptanone is more preferred. The content of the organic solvent in the developer is preferably 80% by mass or more, more preferably 90% by mass or more, still more preferably 95% by mass or more, and particularly preferably 99% by mass or more. Examples of components other than the organic solvent in the developer include water and silicone oil.

Examples of the development method include: a method of immersing the substrate in a tank filled with a developer solution for a fixed period of time (dipping method); and a method of performing development by depositing the developer solution on the surface of the substrate using surface tension for a fixed period of time (coating method). Puddle method); a method of spraying developer on the surface of the substrate (spray method); a method in which developer spray nozzles are scanned at a fixed speed while the developer is continuously sprayed onto a substrate rotating at a fixed speed (dynamic distribution method) )Wait.

<Processing method of substrate, manufacturing method of metal film pattern> The processing method of the substrate of the present invention further includes the step (4-1), In the step (4-1), the resist pattern formed by any of the above methods is used as a mask to form a pattern on the substrate.

In addition, the manufacturing method of the metal film pattern of the present invention further includes the step (4-2), The step (4-2) is to form a metal film using the resist pattern formed by any of the methods described above as a mask.

The processing method of the substrate and the manufacturing method of the metal film pattern use the radiation-sensitive resin composition or the resist film, so even if it does not substantially contain (C) the generation of radiation-sensitive acid as before The agent can also function as a resist film in the previous exposure step or the like, and can process a high-quality substrate pattern and a high-quality metal film pattern separately.

The step (4-1) is a step of forming a pattern on a substrate using a resist pattern formed by any of the methods described as a mask. As a method of forming a pattern on a substrate using a resist pattern as a mask, for example, after forming a resist pattern on the substrate, the pattern is formed on the substrate by a method such as dry etching in a portion where the resist does not exist. Method; or after forming the resist pattern, in the part where the resist does not exist, vapor deposition of the substrate constituents such as chemical vapor deposition (CVD) or other methods such as electroless plating A method of forming a part or all of a substrate by attaching metal.

The step (4-2) is a step of forming a metal film using the resist pattern formed by any of the methods described as a mask, as a method of forming a metal film using the resist pattern as a mask For example, after forming a resist pattern, a method of forming a metal film by attaching a metal to a portion where the resist does not exist by a method such as electroless plating; or forming a resist pattern on the metal film, A method of forming a metal film by removing the metal film in the portion where the resist does not exist by a method such as dry etching. [Example]

Next, the present invention will be specifically described with examples, but the present invention is not limited to the following examples. The measurement methods of various physical properties are shown below.

[Determination of weight average molecular weight (Mw), number average molecular weight (Mn) and degree of dispersion (Mw/Mn)] Regarding the Mw and Mn of the polymer used in the examples, GPC columns (G2000HXL: 2 pieces, G3000HXL: 1 piece, and G4000HXL: 1 piece) manufactured by Tosoh Corporation were used, and the flow rate: 1.0 mL/min , Dissolution solvent: tetrahydrofuran, sample concentration: 1.0% by mass, sample injection volume: 100 μL, column temperature: 40°C, detector: differential refractometer, by using monodisperse polystyrene as the standard The gel permeation chromatography (GPC) method is used for the determination. In addition, the degree of dispersion (Mw/Mn) is calculated from the measurement results of Mw and Mn.

＜[A] Synthesis of polymer＞ The monomers used in the synthesis of each polymer in each example and comparative example are shown below. In addition, in the following synthesis examples, unless otherwise specified, parts by mass means the value when the total mass of the monomers used is 100 parts by mass, and the mole% means the unit used The total number of moles of the body is the value when 100 mole%.

[化14]

[Synthesis Example 1] (Synthesis of polymer (A-1)) The compound (M-1) and the compound (M-4) are dissolved in 1-methoxy-2-propanol (200 parts by mass relative to the amount of all monomers) so that the molar ratio becomes 40/60 . Next, 6 mol% of azobisisobutyronitrile was added as a starting agent with respect to all monomers to prepare a monobody solution. On the other hand, 1-methoxy-2-propanol (100 parts by mass relative to the amount of all monomers) was added to an empty reaction vessel, and heated to 85°C while stirring. Next, the prepared monomer solution was added dropwise over 3 hours, and then further heated at 85°C for 3 hours, and the polymerization reaction was performed for a total of 6 hours. After the completion of the polymerization reaction, the polymerization solution was cooled to room temperature.

After that, the cooled polymerization solution was poured into hexane (500 parts by mass with respect to the polymerization solution), and the precipitated white powder was separated by filtration. After the white powder separated by filtration was washed twice with 100 parts by mass of hexane with respect to the polymerization solution, it was separated by filtration and dissolved in 1-methoxy-2-propanol (300 parts by mass). Next, methanol (500 parts by mass), triethylamine (50 parts by mass), and ultrapure water (10 parts by mass) were added, and the hydrolysis reaction was carried out at 70° C. for 6 hours while stirring.

After the completion of the reaction, the residual solvent was distilled off, and the obtained solid was dissolved in acetone (100 parts by mass). It was added dropwise to 500 parts by mass of water to coagulate the resin, and the obtained solid was separated by filtration. It was dried at 50°C for 12 hours to synthesize a white powdery polymer (A-1).

The Mw of the obtained polymer (A-1) was 5,700, and the Mw/Mn was 1.61.

[Synthesis Example 2-Synthesis Example 18] (Synthesis of Polymer (A-2)-Polymer (A-12)) The monomers were selected according to the recipe in Table 1, and the same operations as in Synthesis Example 1 were performed to synthesize polymers (A-2) to (A-12) and polymer (A-14). In addition, Mw and Mw/Mn of the obtained polymers (A-2) to (A-12) are also shown in Table 1.

The recipe content and preparation results of each synthesis example are shown in Table 1 below.

[Table 1] Table 1 polymer Provide a single body of each structural unit Mw Mw/Mn type Usage (mol%) Containing ratio of structural unit (mol%) type Usage (mol%) Containing ratio of structural unit (mol%) type Usage (mol%) Containing ratio of structural unit (mol%) Synthesis example 1 A-1 M-1 ^a 40 40.3 M-4 60 59.7 - - - 5700 1.61 Synthesis Example 2 A-2 M-1 ^a 40 41.3 M-5 60 58.7 - - - 5800 1.64 Synthesis Example 3 A-3 M-1 ^a 40 43.2 M-6 60 56.8 - - - 6200 1.62 Synthesis Example 4 A-4 M-1 ^a 40 39.8 M-7 60 60.2 - - - 5500 1.54 Synthesis Example 5 A-5 M-1 ^a 40 39.7 M-8 60 60.3 - - - 5400 1.53 Synthesis Example 6 A-6 M-1 ^a 40 45.3 M-9 60 54.7 - - - 6000 1.67 Synthesis Example 7 A-7 M-1 ^a 40 42.2 M-10 60 57.8 - - - 6200 1.50 Synthesis Example 8 A-8 M-1 ^a 40 42.5 M-11 60 57.5 - - - 6100 1.55 Synthesis Example 9 A-9 M-1 ^a 40 41.5 M-12 60 58.5 - - - 5700 1.62 Synthesis Example 10 A-10 M-1 ^a 40 45.2 M-13 60 54.8 - - - 5500 1.61 Synthesis Example 11 A-11 M-1 ^a 40 44.3 M-14 60 55.7 - - - 6100 1.64 Synthesis Example 12 A-12 M-1 ^a M-2 ^a 2020 19.218.3 M-10 60 62.5 - - - 6100 1.53 Synthesis Example 13 A-13 M-2 ^a 40 40.2 M-10 60 59.8 - - - 5800 1.59 Synthesis Example 14 A-14 M-3 ^a 40 40.5 M-10 60 59.5 - - - 5700 1.56 Synthesis Example 15 A-15 M-1 ^a 20 19.3 M-10 60 58.3 M-15 20 22.4 6300 1.55 Synthesis Example 16 A-16 M-1 ^a 20 19.4 M-10 60 57.5 M-16 20 23.1 6200 1.64 Synthesis Example 17 A-17 M-1 ^a 20 19.1 M-10 60 58.2 M-17 20 22.7 5900 1.59 Synthesis Example 18 A-18 M-1 ^a 20 18.9 M-10 60 59.2 M-18 20 21.9 6300 1.64 a: Exist as hydroxystyrene

<Preparation of Radiation Sensitive Resin Composition> The [C] acid generator, [D] acid diffusion control agent, and [B] solvent used in the preparation of the radiation-sensitive resin composition of the Examples and Comparative Examples are shown below.

[[C] Acid Generator] The structural formula of the acid generator is shown below. [化15]

[[D] Acid diffusion control agent] The structural formula of the acid diffusion control agent is shown below. [化16]

[[B]Organic solvent] The organic solvents are shown below. B-1: Propylene glycol monomethyl ether acetate B-2: Propylene glycol 1-monomethyl ether

[Example 1] 100 parts by mass of (A-1) as [A] polymer, 12,200 parts by mass as (B-1) and (B-2) 5,200 parts by mass as [B] organic solvent are mixed, and a 20 nm membrane filter is used Filtering was performed to prepare a radiation-sensitive resin composition (R-1).

[Example 2 to Example 18 and Comparative Example 1] (Radiation-sensitive resin composition (R-2) to radiation-sensitive resin composition (R-18) and radiation-sensitive resin composition (CR-1)) Except having used each component of the kind and compounding quantity shown in following Table 2, it carried out similarly to Example 1, and prepared each radiation-sensitive resin composition.

[Table 2] Table 2 Radiation-sensitive resin composition Resin Mass parts Radiation-sensitive acid generator Mass parts Acid diffusion control agent Relative to the mole% of the radioactive acid generator Solvent Mass parts Example 1 R-1 A-1 100 - - - - B-1/B-2 12200/5200 Example 2 R-2 A-2 100 - - - - B-1/B-2 12200/5200 Example 3 R-3 A-3 100 - - - - B-1/B-2 12200/5200 Example 4 R-4 A-4 100 - - - - B-1/B-2 12200/5200 Example 5 R-5 A-5 100 - - - - B-1/B-2 12200/5200 Example 6 R-6 A-6 100 - - - - B-1/B-2 12200/5200 Example 7 R-7 A-7 100 - - - - B-1/B-2 12200/5200 Example 8 R-8 A-8 100 - - - - B-1/B-2 12200/5200 Example 9 R-9 A-9 100 - - - - B-1/B-2 12200/5200 Example 10 R-10 A-10 100 - - - - B-1/B-2 12200/5200 Example 11 R-11 A-11 100 - - - - B-1/B-2 12200/5200 Example 12 R-12 A-12 100 - - - - B-1/B-2 12200/5200 Example 13 R-13 A-13 100 - - - - B-1/B-2 12200/5200 Example 14 R-14 A-14 100 - - - - B-1/B-2 12200/5200 Example 15 R-15 A-15 100 - - - - B-1/B-2 12200/5200 Example 16 R-16 A-16 100 - - - - B-1/B-2 12200/5200 Example 17 R-17 A-17 100 - - - - B-1/B-2 12200/5200 Example 18 R-18 A-18 100 - - - - B-1/B-2 12200/5200 Comparative example 1 CR-1 A-10 100 C-1 36 D-1 250 B-1/B-2 12200/5200

[Formation of resist pattern by EUV exposure and alkali development] Using a spin coater (CLEAN TRACK ACT12, manufactured by Tokyo Electron), each radiation-sensitive resin composition described in Table 2 was applied to the underlayer film ( AL412 (manufactured by Brewer Science) is a 12-inch silicon wafer surface that is pre-baked (PB) at 100°C for 60 seconds. After that, it was cooled at 23° C. for 30 seconds to form a resist film with a thickness of 20 nm.

Next, the obtained resist film was irradiated with EUV light using an EUV exposure machine (model "NXE3300", manufactured by ASML, NA=0.33, lighting conditions: Dipole). After irradiation, the resist film was developed using a 2.38 wt% TMAH aqueous solution at 23°C for 30 seconds, then washed with water, and then dried to form a positive line and space resist. Agent pattern.

[Evaluation] The sensitivity and resolution of each radiation-sensitive resin composition were evaluated by measuring each of the formed resist patterns according to the following method. Furthermore, the length measurement of the resist pattern uses a scanning electron microscope ("CG-4100" of Hitachi Hightechnologies). The evaluation results are shown in Table 3 below.

[Sensitivity] In the formation of the resist pattern, the exposure amount for forming the 18 nm line and space pattern was set as the optimal exposure amount, and the optimal exposure amount was set as the sensitivity (mJ/cm ² ). Regarding the sensitivity, the case of 100 mJ/cm ² or less was judged as "good", and the case of more than 100 mJ/cm ² was judged as "bad".

[Analysis] In the optimal exposure level, the size of the smallest resist pattern that can be analyzed is measured while changing the size of the mask pattern forming the line and space (1L/1S), and the measured value is set as the analysis性(nm). The smaller the analytic value, the better. Regarding the resolution, the case of less than 18 nm can be evaluated as good, and the case of 18 nm or more can be evaluated as poor.

The formation results of each resist pattern are shown in Table 3 below.

[Table 3] Table 3 Radiation-sensitive resin composition Sensitivity (mJ/cm ² ) Resolution (nm) Example 1 R-1 98 17 Example 2 R-2 97 16 Example 3 R-3 95 16 Example 4 R-4 93 16 Example 5 R-5 95 16 Example 6 R-6 97 16 Example 7 R-7 88 15 Example 8 R-8 90 16 Example 9 R-9 92 16 Example 10 R-10 94 17 Example 11 R-11 95 17 Example 12 R-12 94 16 Example 13 R-13 95 15 Example 14 R-14 89 16 Example 15 R-15 90 15 Example 16 R-16 92 15 Example 17 R-17 93 15 Example 18 R-18 98 17 Comparative example 1 CR-1 105 18

[Synthesis Example 19] (Synthesis of polymer (A-19)) The compound (M-5) and the compound (M-13) were dissolved in 2-butanol so that the molar ratio became 60/40 (mol %) To the ketone (200 parts by mass), AIBN (Azobisisobutyronitrile) (Azobisisobutyronitrile) (8 mol% with respect to the total of 100 mol% of the monomers used) was added as a starting agent to prepare a monomer Solution. Put 2-butanone (100 parts by mass) into an empty reaction vessel, and after flushing with nitrogen for 30 minutes, the inside of the reaction vessel was set to 80° C., while stirring, the monobody solution was added dropwise over 3 hours. The start of dropping was set as the start time of the polymerization reaction, and the polymerization reaction was performed for 6 hours. After the polymerization reaction is completed, the polymerization solution is water-cooled and cooled to below 30°C. The cooled polymerization solution was put into methanol (2,000 parts by mass), and the precipitated white powder was separated by filtration. After washing the white powder separated by filtration twice with methanol, it was separated by filtration, and dried at 50° C. for 10 hours to obtain a white powdery polymer (A-19). The Mw of the polymer (A-19) was 5,700, and the Mw/Mn was 1.61. In addition, as ^{a result of 13} C-NMR analysis, the content ratio of each structural unit derived from (M-5) and (M-13) was 58.5 mol% and 41.5 mol%, respectively.

[Synthesis Example 20] (Synthesis of polymer (A-20)) The monomers were selected according to the recipes in Table 4, and the same operation as in Synthesis Example 1 was performed, thereby synthesizing the polymer (A-20). In addition, the Mw and Mw/Mn of the obtained polymer (A-20) are also shown in Table 4.

The recipe content and preparation results of each synthesis example are shown in Table 4 below.

[Table 4] Table 4 polymer Provide a single body of each structural unit Mw Mw/Mn type Usage (mol%) Containing ratio of structural unit (mol%) type Usage (mol%) Containing ratio of structural unit (mol%) type Usage (mol%) Containing ratio of structural unit (mol%) Synthesis Example 19 A-19 - - - M-5 60 58.5 M-17 40 41.5 5700 1.61 Synthesis Example 20 A-20 - - - M-13 60 56.2 M-17 40 43.8 5800 1.64

<Preparation of Radiation Sensitive Resin Composition> [Example 19] (Radiation-sensitive resin composition (R-19)) 100 parts by mass of (A-19) as [A] polymer, 12,200 parts by mass as (B-1) and (B-2) 5,200 parts by mass as [B] organic solvent were mixed, and a 20 nm membrane filter was used Filtering was performed to prepare a radiation-sensitive resin composition (R-19).

[Example 20] (Radiation-sensitive resin composition (R-20)) Except having used each component of the kind and compounding amount shown in following Table 5, it carried out similarly to Example 19, and prepared each radiation-sensitive resin composition.

[Table 5] Table 5 Radiation-sensitive resin composition Resin Mass parts Radiation-sensitive acid generator Mass parts Acid diffusion control agent Relative to the mole% of the radioactive acid generator Solvent Mass parts Example 19 R-19 A-19 100 - - - - B-1/B-2 12200/5200 Example 20 R-20 A-20 100 - - - - B-1/B-2 12200/5200

[Formation of resist pattern by EUV exposure and alkali development] Using the radiation-sensitive resin composition (R-19) or the radiation-sensitive resin composition (R-20), a positive line and space resist pattern is formed in the same manner as described above.

[Evaluation] The sensitivity and resolution were evaluated for each resist pattern formed as described above in the same manner as described above. The evaluation results are shown in Table 6 below.

[Table 6] Table 6 Radiation-sensitive resin composition Sensitivity (mJ/cm ² ) Resolution (nm) Example 19 R-19 85 16 Example 20 R-20 81 17

As shown in Table 3 and Table 6, the sensitivity and resolution in the exposure step of the radiation-sensitive resin composition of the example were both good. On the other hand, the radiation-sensitive resin composition of the comparative example is not good compared with the result of the Example in the said performance. In this way, it can be seen that the radiation-sensitive resin composition according to the embodiment of the present invention is excellent in sensitivity and resolution. [Industrial availability]

As described above, according to the radiation-sensitive resin composition and resist pattern forming method of the present invention, compared with the previous ones, it is possible to exhibit superior performance in terms of sensitivity, resolution, and the like. The radiation-sensitive resin composition and the resist pattern forming method of the present invention can be preferably used in the formation of fine resist patterns in the lithography step of various electronic devices such as semiconductor devices (devices) and liquid crystal devices. .

without

without

Claims (17)

A method for forming a resist pattern includes: Step (1), forming (C) a resist film with a radiation-sensitive acid generator content of 0.1% by mass or less; Step (2), performing extreme ultraviolet or electron beam exposure on the resist film; and In step (3), the resist film exposed in the step (2) is developed. The method for forming a resist pattern according to claim 1, wherein in the step (1), the resist film is formed of (A) a radiation-sensitive resin composition, the radiation-sensitive resin composition comprising (A1) A resin whose solubility changes by extreme ultraviolet or electron beam exposure in the absence of a radiation-sensitive acid generator. The method for forming a resist pattern according to claim 1 or claim 2, wherein in the step (1), the resist film is formed of (A) a radiation-sensitive resin composition, and in the step (A) ) In the radiation-sensitive resin composition, the (C) radiation-sensitive acid generator is 0.1% by mass or less with respect to the total of the components other than the (B) solvent. The method for forming a resist pattern according to claim 1 or claim 2, wherein in the step (1), the resist film is formed of (A) a radiation-sensitive resin composition, and the (A) The radiation-sensitive resin composition does not contain a radiation-sensitive acid generator. The method for forming a resist pattern according to claim 2, wherein the (A1) resin whose solubility is changed is a resin whose solubility is changed to water-soluble or alkali-soluble. The method for forming a resist pattern according to claim 1 or claim 2, wherein in the step (3), an organic solvent is used to develop a negative pattern. The method for forming a resist pattern according to claim 1 or claim 2, wherein in the step (3), an alkaline developer is used to develop a positive pattern. A method for processing a substrate, including step (4-1), the step (4-1) is formed by the resist pattern forming method as described in any one of claim 1 to claim 7 The resist pattern of is used as a mask to form a pattern on the substrate. A method for manufacturing a metal film pattern, comprising step (4-2), the step (4-2) is to use the resist pattern forming method as described in any one of claim 1 to claim 7 The formed resist pattern serves as a mask to form a metal film. A radiation-sensitive resin composition containing (A2) a resin containing a group dissociated by extreme ultraviolet or electron beam exposure, (B) a solvent, and (C) a radiation-sensitive acid generator, in which the radiation-sensitive acid generator In the resin composition, the (C) radiation-sensitive acid generator is 0.1% by mass or less with respect to the total of the components other than the (B) solvent. A radiation-sensitive resin composition consisting only of (A2) a resin containing groups dissociated by extreme ultraviolet or electron beam exposure, and (B) a solvent. The radiation-sensitive resin composition according to claim 10 or claim 11, wherein the (A2) resin containing a dissociated group is a resin containing a group that dissociates to generate a carboxylic acid structure. The radiation-sensitive resin composition according to claim 10 or claim 11, wherein the (A2) resin containing a dissociated group contains a structural unit represented by the following formula (2);

In the formula (2), R ⁷ is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group; R ⁸ is a hydrogen atom or a monovalent hydrocarbon group with 1 to 20 carbon atoms; R ⁹ and R ¹⁰ are each independently A monovalent chain hydrocarbon group of 1 to 20 carbons substituted with or not substituted with a fluorine atom, a monovalent alicyclic hydrocarbon group of 3 to 20 carbons substituted with or not substituted with a fluorine atom, or a carbon number A monovalent aromatic hydrocarbon group of 5-20, or a divalent lipid with 3-20 carbons substituted by fluorine atoms or not substituted by fluorine atoms, which is formed by combining these groups together with the bonded carbon atoms Cyclic group; in addition, ^{any one of R 8} to R ¹⁰ and/or the alicyclic group when the alicyclic group is present may have an unsaturated bond; in addition, R ^{8 is also included} When a plurality of any of to R ¹⁰ together form an alicyclic structure. The radiation-sensitive resin composition according to claim 13, wherein the R ⁹ and R ¹⁰ are divalent saturated or unsaturated with 3 to 20 carbon atoms that are combined with each other and form together with the bonded carbon atoms Alicyclic group. The radiation-sensitive resin composition according to claim 13, wherein said R ⁸ is a hydrogen atom, a fluorine atom substituted or unsubstituted monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms, or a carbon number 5-20 monovalent aromatic hydrocarbon group. The radiation-sensitive resin composition according to claim 10 or claim 11, wherein the (A2) resin containing a dissociated group contains: a structural unit having a group that dissociates to generate a carboxylic acid structure; At least one structural unit among the structural unit of the sexual hydroxyl group and the structural unit having a polar group. The radiation-sensitive resin composition according to claim 16, wherein the structural unit having a polar group contains a structure selected from a structural unit having an alcoholic hydroxyl group, a structural unit having a lactone structure, and a structure having a cyclic carbonate structure At least one of a unit and a structural unit having a sultone structure.